That looks really cool. I built the cpuville kit a few years ago but its I/O decoding was borked, it didn't expose enough control signals through its extension mechanism, and its pin headers were at an odd spacing so you couldn't just plug a prototyping board onto it.

I designed a and built new I/O extender to fix all those problems but PCB design is not fun for me so I never made a PCB for it.

This one looks to have none of those problems.